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In computer architecture, speedup is a metric for improvement in performance between two systems processing the same problem. More technically, is it the improvement in speed of execution of a task executed on two similar architectures with different resources. The notion of speedup was established by Amdahl's law, which was particularly focused on parallel processing. However, speedup can be used more generally to show the effect on performance after any resource enhancement. ==Definitions== Speedup can be defined for two different types of quantities: ''latency'' and ''throughput''. ''Latency'' of an architecture is the reciprocal of the execution speed of a task: : where * ''v'' is the execution speed of the task; * ''T'' is the execution time of the task; * ''W'' is the execution workload of the task. ''Throughput'' of an architecture is the execution rate of a task: : where * ''ρ'' is the execution density (e.g., the number of stages in an instruction pipeline for a pipelined architecture); * ''A'' is the execution capacity (e.g., the number of processors for a parallel architecture). Latency is often measured in seconds per unit of execution workload. Throughput is often measured in units of execution workload per second. Another frequent unit of throughput is the instruction per cycle (IPC). Its reciprocal, the cycle per instruction (CPI), is another frequent unit of latency. Speedup is dimensionless and defined differently for each type of quantity so that it is a consistent metric. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Speedup」の詳細全文を読む スポンサード リンク
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